Method of fabricating a thin-film transistor

ABSTRACT

There is provided a method of manufacturing a thin-film device, the method including forming a first substrate on a supporting base by a coating method, the first substrate being formed by using a resin material; forming a second substrate on the first substrate by using any one of a thermosetting resin and energy ray-curable resin; forming an active element on the second substrate; and removing the supporting base from the first substrate. The resin material used to form the first substrate has a glass transition temperature of at least 180° C.

BACKGROUND

The present disclosure relates to a thin-film device, a method ofmanufacturing the thin-film device, and a method of manufacturing animage display apparatus.

A field effect transistor (FET) includes thin-film transistor (TFT)which is currently used in many types of electronic equipment. Forexample, the FET has a configuration including a channel forming regionand source/drain electrodes which are each formed in a siliconsemiconductor substrate or a layer of a silicon semiconductor material,a gate insulating layer which is formed by using SiO₂ on a surface ofthe silicon semiconductor substrate or layer of a silicon semiconductormaterial, and a gate electrode that is formed so as to face the channelforming layer through the gate insulating layer. The FET having thisconfiguration is referred to as a top gate-type FET for convenience ofdescription. Alternatively, the FET has another configuration includingthe gate electrode formed on a substrate, the gate insulating layerwhich is formed by using SiO₂ so as to overlie the gate electrode andsubstrate, and the channel forming region and source/drain electrodeswhich are formed on the gate insulating layer. The FET having thisconfiguration is referred to as a bottom gate-type FET for convenienceof description. Expensive semiconductor-manufacturing equipment is usedto produce the FET having such configurations, and the decrease ofproduction costs is therefore strongly demanded.

In recent years, electronic devices in which a thin film made from anorganic semiconductor material is used have been intensely developed,and organic electronic devices (hereinafter simply referred to asorganic devices, where appropriate) such as an organic transistor,organic light emitting device, and organic solar battery attractattention. The organic devices are developed to finally provideadvantages including reduced costs, reduced weight, sufficientelasticity, and high performance. As compared with inorganic materialstypified by silicon, the organic semiconductor materials have severaladvantages such as: (1) enabling a large-area organic device to beproduced through an easy process at low temperature, (2) enabling anelastic organic device to be produced, and (3) enabling the performanceand physical properties of the organic devices to be controlled as aresult of modifying molecules contained in organic materials into adesired form.

In particular, study of coating film-forming techniques such as aprinting technique has been developed as an easy process at lowtemperature (see WO2003/016599).

In order to produce the organic devices through an easy process at lowtemperature, various types of layers other than an active layer(channel-forming region, for instance) are also obviously formed at alow temperature process. Therefore, a study has been advanced to form aninsulating film from the organic materials (specifically a coatingmaterial formed as a result of melting a polymer), and a study has beensimilarly advanced to form various electrodes from a material containingdispersed metallic nanoparticles (specifically silver paste) whichenable conductivity to be secured after being sintered at lowtemperature.

SUMMARY

For example, since organic transistors can be produced through a lowtemperature process, a plastic film can be used in place of atraditional silicon wafer to form a substrate. Although the plastic filmis an elastic material with a light weight, it is significantlydifficult to handle the plastic film alone. A supporting base istherefore used in the production of the organic transistors. A techniqueis accordingly typically used, in which a solution of a polyimide resin,for instance, is applied to a supporting base such as a glass substrateto form a polyimide film on the supporting base. In this case, however,the polyimide film has a difficulty in being removed from the supportingbase. In general, a laser ablation method using an excimer laser or thelike is therefore employed to remove the polyimide film from thesupporting base [see Japanese Unexamined Patent Application Publication(Translation of PCT Application) No. 2007-512568], and a large-scaleequipment is used in this case. Another technique is also typicallyemployed, in which the plastic film is removed from the supporting baseas a result of removing a sacrificing layer, which has been formed inadvance, by the laser ablation method (see Japanese Unexamined PatentApplication Publication No. 2001-057432). Unfortunately, large-scaleequipment is used also in this case.

It is accordingly desirable to provide the following: a method ofmanufacturing a thin-film device, the method enabling an active elementto be produced through a simple and easy process without large-scaleequipment; a thin-film device which is produced by the method; a methodof manufacturing an image display apparatus, the method including themethod of manufacturing the thin-film device.

According to an embodiment of the present disclosure, there is provideda method of manufacturing a thin-film device, the method includingforming a first substrate on a supporting base by a coating method, thefirst substrate being formed by using a resin material; forming a secondsubstrate on the first substrate by using any one of a thermosettingresin and energy ray-curable resin; forming an active element on thesecond substrate; and removing the supporting base from the firstsubstrate. In this method, the resin material used for the firstsubstrate has a glass transition temperature of at least 180° C.

According to another embodiment of the present disclosure, there isprovided a method of manufacturing a thin-film device, the methodincluding forming a first substrate on a supporting base by a coatingmethod, the first substrate being formed by using a resin material;forming a second substrate on the first substrate by using any one of athermosetting resin and energy ray-curable resin; forming an activeelement on the second substrate; and removing the supporting base fromthe first substrate. In this method, the resin material used for thefirst substrate has a glass transition temperature higher than themaximum of a processing temperature during the formation of the activeelement.

According to another embodiment of the present disclosure, there isprovided a method of manufacturing a thin-film device, the methodincluding forming a first substrate on a supporting base by a coatingmethod, the first substrate being formed by using an amorphousthermoplastic resin; forming a second substrate on the first substrateby using any one of a thermosetting resin and an ultraviolet curableresin; forming an active element on the second substrate; and removingthe supporting base from the first substrate.

According to another embodiment of the present disclosure, there isprovided a method of manufacturing an image display apparatus, themethod including the method of manufacturing a thin-film deviceaccording to the above embodiments of the present disclosure.

According to another embodiment of the present disclosure, there isprovided a thin-film device including a first substrate, a secondsubstrate formed on the first substrate, and an active element formed onthe second substrate. In the thin-film device, a resin material is usedto form the first substrate and has a glass transition temperature of atleast 180° C., and any one of a thermosetting resin and energyray-curable resin is used to form the second substrate.

According to another embodiment of the present disclosure, there isprovided a thin-film device including a first substrate, a secondsubstrate formed on the first substrate, and an active element formed onthe second substrate. In the thin-film device, a resin material is usedto form the first substrate and has a glass transition temperaturehigher than the maximum of a processing temperature during the formationof the active element of the thin-film device, and any one of athermosetting resin and energy ray-curable resin is used to form thesecond substrate.

According to another embodiment of the present disclosure, there isprovided a thin-film device including a first substrate, a secondsubstrate formed on the first substrate, and an active element formed onthe second substrate. In the thin-film device, an amorphousthermoplastic resin is used to form the first substrate, and any one ofa thermosetting resin and an ultraviolet curable resin is used to formthe second substrate.

In the methods of manufacturing a thin-film device and method ofmanufacturing an image display apparatus according to the aboveembodiments of the present disclosure, the active element is formed on atwo-layered structure of the first and second substrates, and thesupporting base is then removed from the first substrate. A thin-filmdevice can be therefore manufactured through a simple and easy processwithout large-scale manufacturing equipment. Furthermore, the firstsubstrate is covered with the second substrate, and the active elementis formed on the second substrate in a state in which the firstsubstrate is protected. The first substrate can be therefore steadilyprevented from being damaged during the formation of the active element.Moreover, since the first substrate is formed on the supporting base bya coating method, the first substrate can be easily formed, and airbubbles are less likely to be caused between the supporting base and thefirst substrate. In the thin-film devices according to the aboveembodiments of the present disclosure, the materials used for the firstand second substrates and the properties, details, and particulars ofthe materials are defined. The thin-film device can be thereforeproduced through a simple and easy process without large-scalemanufacturing equipment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a partial cross-sectional view schematically illustrating athin-film device of an example 1;

FIG. 1B is a partial cross-sectional view schematically illustrating asupporting base and other portions and serves to describe a method ofmanufacturing the thin-film device of the example 1;

FIG. 2A is a partial cross-sectional view schematically illustrating athin-film device of an example 2;

FIG. 2B is a partial cross-sectional view schematically illustrating athin-film device of an example 3;

FIG. 3A is a partial cross-sectional view schematically illustrating athin-film device of an example 4; and

FIG. 3B is a partial cross-sectional view schematically illustrating athin-film device of an example 6.

DETAILED DESCRIPTION OF EMBODIMENTS

Although embodiments of the present disclosure will be described basedon examples with reference to the drawings, embodiments of the presentdisclosure are not limited to the examples. Various numerals andcomponents in the following examples are nothing but an example.Description will be made in the following order: (1) thin-film devicesof first to third embodiments of the present disclosure, a method ofmanufacturing the thin-film devices, a method of manufacturing an imagedisplay apparatus, and general description; (2) an example 1 (thethin-film devices of the first to third embodiments of the presentdisclosure, the method of manufacturing the thin-film devices, and themethod of manufacturing an image display apparatus); (3) example 2 (amodification of the example 1); (4) example 3 (another modification ofthe example 1); (5) example 4 (another modification of the example 1);(6) example 5 (another modification of the example 1); and (7) example 6(another modification of the example 1) and others.

In the thin-film device of the first embodiment of the presentdisclosure, the method of manufacturing the thin-film device of thefirst embodiment, or the method of manufacturing an image displayapparatus, which includes the method of manufacturing the thin-filmdevice of the first embodiment (hereinafter collectively referred to as“the first embodiment of the present disclosure”), a resin materialwhich is not cured or cross-linked can be employed as a resin materialused for a first substrate, and a material used for a second substratecan contain the resin material used for the first substrate. Since thematerial used for the second material is employed in this manner, anexcellent advantage can be provided, in which removal at the interfacebetween the first and second substrates can be eliminated. In the firstembodiment of the present disclosure having such a desirable formation,a peel strength (in particular, 90° peel strength) is preferablyexhibited to a supporting base in the range from 1.0 N/cm (0.1 kgf/cm)to 4.9 N/cm (0.5 kgf/cm). The 90° peel strength is defined in accordancewith JIS K 6854-1:1999. Specific examples of the resin material used forthe first substrate include a polysulfone resin, polyether sulfoneresin, and polyetherimide resin. Specific examples of the material usedfor the second substrate include a polysulfone-containing resin such asa resin which is formed as a result of mixing polyisocyanate or melamineresin as a cross-linker that reacts with a hydroxyl group with apolysulfone resin containing a hydroxyl group at an end group thereof.

In the thin-film device of the second embodiment of the presentdisclosure, the method of manufacturing the thin-film device of thesecond embodiment, or the method of manufacturing an image displayapparatus, which includes the method of manufacturing the thin-filmdevice of the second embodiment (hereinafter collectively referred to as“the second embodiment of the present disclosure”), the resin materialused for the first substrate desirably has a glass transitiontemperature of 180° C. or higher. In the second embodiment of thepresent disclosure having such a desirable formation, a peel strength(in particular, 90° peel strength) is preferably exhibited to thesupporting base in the range from 1.0 N/cm (0.1 kgf/cm) to 4.9 N/cm (0.5kgf/cm).

In the thin-film device of the third embodiment of the presentdisclosure, the method of manufacturing the thin-film device of thethird embodiment, or the method of manufacturing an image displayapparatus, which includes the method of manufacturing the thin-filmdevice of the third embodiment (hereinafter collectively referred to as“the third embodiment of the present disclosure”), an amorphousthermoplastic resin is used to form the first substrate, and apolysulfone-based resin may be employed as the amorphous thermoplasticresin. In particular, a polysulfone resin, polyether sulfone resin, orpolyetherimide resin may be employed as the thermoplastic resin used forthe first substrate. In the third embodiment of the present disclosurehaving such a desirable formation, a thermosetting resin is used to formthe second substrate, and an epoxy-based resin may be employed as thethermosetting resin. Specific examples of a preferable combination ofthe material used for the first substrate and the material used for thesecond substrate include a polysulfone resin and epoxy-based resin, apolyether sulfone resin and epoxy-based resin, and a polyetherimideresin and epoxy-based resin.

In the first to third embodiments of the present disclosure havingdesirable formation and structure described above, an active element maybe configured so as to include a first and second electrodes, an activelayer formed between the first and second electrodes, and a controlelectrode which faces the active layer through an insulating layer. Inthis case, the active element may be specifically provided as an organictransistor, more specifically as a three-terminal device in the form ofa FET including a TFT. The active element may be configured so as tohave the following structure: source/drain electrodes corresponding tothe first and second electrodes, a gate electrode corresponding to thecontrol electrode, a gate insulating layer corresponding to theinsulating layer, and a channel-forming region corresponding to theactive layer. Furthermore, in the first to third embodiments of thepresent disclosure having desirable formation and structure describedabove, the active element may be configured so as to include the firstelectrode, the second electrode, and the active layer formed between thefirst and second electrodes. In this case, the active element may bespecifically provided as a two-terminal device in the form of varioustypes of sensors such as a photoelectric transducer, solar battery,image sensor, and optical sensor. In this case, an organic semiconductormaterial may be used to form the active layer.

Furthermore, in the first to third embodiments of the present disclosurehaving desirable formation and structure described above, examples ofthe active element include an organic electroluminescence device(organic EL device), microcapsule-type electrophoretic display device,semiconductor light-emitting device [semiconductor laser device orlight-emitting diode (LED)], and liquid crystal display device.Meanwhile, the organic EL device, microcapsule-type electrophoreticdisplay device, semiconductor light-emitting device, and liquid crystaldisplay device may be formed so as to have traditional formation andstructure.

In the second embodiment of the present disclosure having desirableformation and composition described above, examples of the amorphousthermoplastic resin include styrene-based resins such a polystyreneresin, acrylonitrile-butadiene-styrene (ABS) resin,acrylonitrile-ethylene-styrene (AES) resin, and acrylonitrile-styrene(AS) resin; methacrylic resins such as a polymethylmethacrylate (PMMA);polycarbonate resins (including a linear polycarbonate resin and apolycarbonate resin having branching on the main chain); polyphenyleneether (PPE)-based resins such as modified polyphenylene ether;polysulfone resin; polyether sulfone resin; polyarylate resin;polyetherimide resin; polyamide-imide resin; polyether ketone resin;polyetheretherketone resin; polyester carbonate resin; cyclic olefinpolymer (COP); cyclic olefin copolymer (COC); and elastomer. Examples ofthe resin used for the second substrate include thermosetting resins orultraviolet curable resins such as a phenol resin, urea resin, melamineresin, xylene resin, xylene-formaldehyde resin, diallyl phthalate resin,furan resin, ketone-formaldehyde resin, urea-formaldehyde resin, anilineresin, alkyd resin, unsaturated polyester resin, and epoxy resin.

In general, whether the thermoplastic resin is the amorphousthermoplastic resin or not is determined by measurement of a specificmelting point (temperature that exhibits drastic heat absorption) bydifferential scanning calorimetry (DSC). The resin in which a specificmelting point is not measured is the amorphous thermoplastic resin. Onthe other hand, the resin in which a specific melting point is measuredis a crystalline thermoplastic resin.

Examples of an image display apparatus manufactured by the method ofmanufacturing an image display apparatus according to an embodiment ofthe present disclosure and an image display apparatus in which thethin-film devices of the first to third embodiments of the presentdisclosure are incorporated include various types of image displayapparatuses such as a desktop personal computer, laptop, mobile personalcomputer, personal digital assistant (PDA), cellular phone, gamemachine, electronic book, electronic paper (for example, electronicnewspaper), bulletin board (for example, signboard, poster, andblackboard), copying machine, rewritable paper used in place of printingpaper, calculator, display of household electric appliance, card displayof a point card or the like, electronic advertisement, and electronicpoint of purchase (POP) advertisement. Furthermore, various types oflightning systems are also included.

The first substrate is formed on the supporting base by a coating methodusing the resin material. Examples of the coating method includetechniques of applying a liquid material, such as various types ofprinting techniques including screen printing, ink-jet printing, offsetprinting, reverse offset printing, gravure printing, gravure offsetprinting, relief printing, flexographic printing, and microcontactprinting; a spin coat method; various types of coating techniquesincluding air doctor coating, blade coating, rod coating, knife coating,squeeze coating, reverse roll coating, transfer roll coating, gravurecoating, kiss coating, cast coating, spray coating, slit coating, slitorifice coating, calender coating, cast coating, capillary coating, barcoating, and dip coating; spraying; a technique utilizing a dispenser;and stamping.

In order to form the first substrate on the supporting base by using theresin material, a solution in which the resin material is dissolved isprepared. Examples of a solvent include water; alcohols such as ethylalcohol, isopropyl alcohol, and butyl alcohol; aromatics such as tolueneand xylene; ketones such as acetone and 2-butanone; and hydrocarbonssuch as propylene glycol monomethyl ether acetate (PGMEA), and thesesolvents may be appropriately used alone or in combination. In additionto the organic solvents, additives such as a surfactant and levelingagent may be added. Furthermore, materials other than polymericmaterials may be added depending on aims such as imparting applicabilityand other properties. Specific examples of such materials include asilica filler and a glass fiber.

A material which does not chemically react with the supporting base ispreferably employed as the resin material used for the first substrate.In this case, the expression “not chemically react with the supportingbase” means the following: in the case of using glass as the supportingbase, for example, the material does not have a reaction group whichcauses chemical reaction with a hydroxyl group on a surface of theglass. The supporting base is removed from the first substrate, and theremoval can be mechanically conducted. In particular, cut lines are madein the first and second substrates overlying the supporting base bymachine or hand. Then, the supporting base may be removed from the firstsubstrate by machine or hand, or the first substrate may be removed fromthe supporting base by machine or hand. Alternatively, cut lines aremade in the first and second substrates overlying the supporting base bymachine or hand. Then, water is made to intrude from the cut lines,thereby being able to remove the supporting base from the firstsubstrate or being able to remove the first substrate from thesupporting base. The first substrate may have a thickness which enablesthe thin-film device to be steadily supported and which appropriatelyenables elasticity (flexibility) to be imparted to the thin-film device.For instance, the first substrate may have a thickness that is in therange from 2×10⁻⁵ m to 2×10⁻⁴ m. The second substrate may have athickness which enables the first substrate to be steadily protectedfrom a ketone solvent and which appropriately enables elasticity(flexibility) to be imparted to the thin-film device. For example, thesecond substrate may have a thickness that is in the range from 1 μm to10 μm. The thin-film element is formed on the second substrate, and thesecond substrate therefore preferably has insulating properties.

Although the various types of coating methods described above can beused as the technique of forming the second substrate on the firstsubstrate, such a technique is not limited to the above coating methods.A technique may be employed, in which the second substrate ispreliminarily prepared in the form of a sheet and is then stacked on thefirst substrate.

In the case of configuring the active element in the form of a bottomgate and bottom contact-type TFT, the TFT can be manufactured throughthe following processes: (a) forming the gate electrode on the secondsubstrate and then forming the gate insulating layer on the entiresurface of the resultant product; (b) forming the source/drainelectrodes on the gate insulating layer; and (c) forming thechannel-forming region so as to overlie the gate insulating layer at aposition at least between the source/drain electrodes, thechannel-forming region being formed as a layer of an organicsemiconductor material. The bottom gate and bottom contact-type TFT has(A) the gate electrode formed on the second substrate; (B) the gateinsulating layer formed on the gate electrode and the second substrate;(C) the source/drain electrodes formed on the gate insulating layer; and(D) the channel-forming region formed between the source/drainelectrodes so as to overlie the gate insulating layer, thechannel-forming region being formed as a layer of an organicsemiconductor material.

In the case of configuring the active element in the form of a bottomgate and top contact-type TFT, the TFT can be manufactured through thefollowing processes: (a) forming the gate electrode on the secondsubstrate and then forming the gate insulating layer on the entiresurface of the resultant product; (b) forming the channel-forming regionand channel-forming region extension on the gate insulating layer, eachbeing formed as a layer of an organic semiconductor material; and (c)forming the source/drain electrodes on the channel-forming regionextension. The bottom gate and top contact-type TFT has (A) the gateelectrode formed on the second substrate; (B) the gate insulating layerformed on the gate electrode and the second substrate; (C) thechannel-forming region and channel-forming region extension formed onthe gate insulating layer, each being formed as a layer of an organicsemiconductor material; and (D) the source/drain electrodes formed onthe channel-forming region extension.

Furthermore, in the case of configuring the active element in the formof a top gate and bottom contact-type TFT, the TFT can be manufacturedthrough the following processes: (a) forming the source/drain electrodeson the second substrate; (b) forming the channel-forming region on theentire surface of the resultant product, the channel-forming regionbeing formed as a layer of an organic semiconductor material; and (c)forming the gate insulating layer on the entire surface of the resultantproduct and then forming the gate electrode on the gate insulating layerso as to overlie the channel-forming region. The top gate and bottomcontact-type TFT has (A) the source and drain electrodes formed on thesecond substrate; (B) the channel-forming region formed on the secondsubstrate between the source/drain electrodes, the channel-formingregion being formed as a layer of an organic semiconductor material; (C)the gate insulating layer formed on the channel-forming region; and (D)the gate electrode formed on the gate insulating layer.

Furthermore, in the case of configuring the active element in the form atop gate and top contact-type TFT, the TFT can be manufactured throughthe following processes: (a) forming the channel-forming region andchannel-forming region extension on the second substrate, each beingformed as a layer of an organic semiconductor material; (b) forming thesource/drain electrodes on the channel-forming region extension; and (c)forming the gate insulating layer on the entire surface of the resultantproduct and then forming the gate electrode on the gate insulating layerso as to overlie the channel-forming region. The top gate and topcontact-type TFT has (A) the channel-forming region and channel-formingregion extension formed on the second substrate, each being formed as alayer of an organic semiconductor material; (B) the source/drainelectrodes formed on the channel-forming region extension; (C) the gateinsulating layer formed on the source/drain electrodes and on thechannel-forming region; and (D) the gate electrode formed on the gateinsulating layer.

The active element can be formed so as to have a mechanism in whichelectric current flowing from the first electrode toward the secondelectrode through the active layer is controlled by application of avoltage to the control electrode. In particular, as described above, theactive element can be formed as a FET (including TFT) so as to have thefollowing configuration: the control electrode corresponds to the gateelectrode; the first and second electrodes correspond to thesource/drain electrodes; the insulating layer corresponds to the gateinsulating layer; and the active layer corresponds to thechannel-forming region. Alternatively, the active element can beconfigured as a light-emitting device (including an organiclight-emitting device and organic light-emitting transistor) in whichthe active layer emits light as a result of applying a voltage to thecontrol electrode and the first and second electrodes. In thelight-emitting device, the organic semiconductor material used for theactive layer has a function to store electric charges in response tomodulation by application of a voltage to the control electrode and toemit light resulting from recombination of injected electrons and holes.Examples of the organic semiconductor material used for the active layerbroadly include an organic semiconductor material having p-typeconductivity and non-doped organic semiconductor material. In alight-emitting device (organic light-emitting transistor) which has theactive layer formed by using the organic semiconductor material havingp-type conductivity, emission intensity is proportional to the absolutevalue of a drain current, and light can be modulated in response to agate voltage and a voltage applied between the source/drain electrodes.Meanwhile, whether the active element functions as the FET orlight-emitting device depends on a state in which a voltage is appliedto the first and second electrodes (bias). A bias voltage is applied soas not to cause electron injection from the second electrode, and thecontrol electrode is then modulated in such a state, thereby causing acurrent to flow from the first electrode toward the second electrode.Transistors function in this manner. In the case of increasing a biasvoltage applied to the first and second electrodes in a state in whichholes are sufficiently stored, electrons start to be injected, and theelectrons recombine with the holes with the result that light isemitted. Furthermore, the active element may be configured as aphotoelectric transducer in which current flows between the first andsecond electrodes as a result of emitting light to the active layer. Inthe case of forming the active element as the photoelectric transducer,the photoelectric transducer is used to configure, for example, a solarbattery and image sensor. In this case, a voltage may be or may not beapplied to the control electrode. In the case of applying a voltage tothe control electrode, the application of a voltage to the controlelectrode enables a flowing current to be modulated. In the case offorming the active element as a light-emitting device or photoelectrictransducer, for example, the light-emitting device or photoelectrictransducer may have formation or structure the same as those of any oneof the four types of TFTs describe above.

Examples of the organic semiconductor material includedioxaanthanthrene-based compounds such as polythiophene,poly-3-hexylthiophene (P3HT) in which a hexyl group is introduced intopolythiophene, pentacene(2,3,6,7-dibenzoanthracene),peri-Xanthenoxanthene; polyanthracene; naphthacene; hexacene; heptacene;dibenzopentacene; tetrabenzopentacene; chrysene; perylene; coronene;Terrylene; ovalene; quaterrylene; circumanthracene; benzopyrene;dibenzopyrene; triphenylene; polypyrrole; polyaniline; polyacetylene;polydiacetylene; polyphenylene; polyfuran; polyindole;polyvinylcarbazole; polyselenophene; polytellurophene;polyisothianaphthene; polycarbazole; polyphenylene sulfide;polyphenylene vinylene; polyvinylene sulfide; polythienylene vinylene;polynaphthalene; polypyrene; polyazulene; phthalocyanine typified bycopper phthalocyanine; merocyanine; hemicyanine;polyethylenedioxythiophene; pyridazine; naphthalenetetracarboxylicdiimide; poly(3,4-ethylene dioxythiophene)/polystyrene sulfonate(PEDOT/PSS); and quinacridone. Furthermore, other examples of theorganic semiconductor material include a compound selected from thegroup consisting of a condensation polycyclic aromatic compound,porphyrin-based derivative, phenylvinylidene-based conjugated oligomer,and thiophene-based conjugated oligomer. Specific examples of such acompound include a condensation polycyclic aromatic compound such asacene-based molecules (pentacene and tetracene, for instance),porphyrin-based molecules, and conjugated oligomer (phenylvinylidenetype and thiophene type, for instance).

Moreover, other examples of the organic semiconductor materials includeporphyrin; 4,4′-biphenyldithiol (BPDT); 4,4′-diisocyanobiphenyl;4,4′-diisocyano-p-terphenyl;2,5-bis(5′-thioacetyl-2′-thiophenyl)thiophene;2,5-bis(5′-thioacetoxyl-2′-thiophenyl)thiophene; 4,4′-diisocyanophenyl;benzidine(biphenyl-4,4′-diamine); tetracyanoquinodimethane (TCNQ);charge-transfer complexes such as a tetrathiafulvalene (TTF)-TCNQcomplex, bisethylenetetrathiafulvalene (BEDTTTF)-perchloric acidcomplex, BEDTTTF-iodine complex, and TCNQ-iodine complex;4,4′-biphenyldicarboxylic acid;1,4-di(4-thiophenylacetylinyl)-2-ethylbenzene;1,4-di(4-isocyanophenylacetylinyl)-2-ethylbenzene; dendrimer; fullerenesuch as C60, C70, C76, C78, and C84;1,4-di(4-thiophenylethynyl)-2-ethylbenzene;2,2″-dihydroxy-1,1′:4′,1″-terphenyl; 4,4′-biphenyl diethanal;4,4′-biphenyldiol; 4,4′-biphenyl diisocyanate; 1,4-diacetylbenzene;diethyl biphenyl-4,4′-dicarboxylate; benzo[1,2-c; 3,4-c′;5,6-c″]tris[1,2]dithiol-1,4,7-trithione; α-sexithiophene;tetrathiotetracene; tetraselenotetracene; tetratellurotetracene;poly(3-alkylthiophene); poly(3-thiophene-β-ethanesulfonic acid);poly(N-alkyl pyrrole)poly(3-alkyl pyrrole); poly(3,4-dialkylpyrrole);poly(2,2′-thienylpyrrole); and poly(dibenzothiophene sulfide).

The active layer and channel-forming region (layer of the organicmaterial) may appropriately contain a polymer. A polymer which can bedissolved in an organic solvent may be used. Specific examples of thepolymer (organic binder and another type of binder) include polystyrene,poly-α-methylstyrene, and polyolefin. In addition, additives (forexample, doping materials such as n-type dopant and p-type dopant) maybe also contained if necessary.

Examples of the solvent used for preparing a solution of the organicsemiconductor material include aromatics such as toluene, xylene,mesitylene, and tetralin; ketones such as cyclopentanone andcyclohexanone; and hydrocarbons such as decalin. Among these, materialshaving relatively high boiling point, such as mesitylene, tetralin, anddecalin, are preferably used in view of transistor characteristics andprevention of drastic drying of the layer of the organic semiconductormaterial during the formation thereof.

A coating method can be used as a method of forming the active layer,channel-forming region, and channel-forming region extension. In thiscase, traditional coating methods can be used without problems. Forexample, the various types of coating methods described above may beemployed in particular.

Examples of the supporting base (supporting substrate) include varioustypes of glass substrates, various types of glass substrate having asurface on which an insulating film is formed, a quartz substrate, aquarts substrate having a surface on which an insulating film is formed,a silicon substrate having a surface on which an insulating film isformed, sapphire substrate, and metallic substrate formed by usingvarious types of alloys, such as stainless steel, and various types ofmetals.

Examples of a material used for the control electrode, first electrode,second electrode, gate electrode, and source/drain electrodes includemetals such as platinum (Pt), gold (Au), palladium (Pd), chromium (Cr),molybdenum (Mo), nickel (Ni), aluminum (Al), silver (Ag), tantalum (Ta),tungsten (W), copper (Cu), titanium (Ti), indium (In), tin (Sn), iron(Fe), cobalt (Co), zinc (Zn), and magnesium (Mg); alloys containingthese metals; conductive particles containing such metals; conductiveparticles containing alloys of such metals; and conductive materialssuch as polysilicon containing a dopant. The electrodes may beconfigured so as to have a structure in which layers containing theabove materials are stacked. Other examples of the material used for thecontrol electrode, first electrode, second electrode, gate electrode,and source/drain electrodes include organic materials (conductivepolymers) such as PEDOT/PSS and polyaniline. The control electrode,first electrode, second electrode, gate electrode, and source/drainelectrodes may be formed by using the same or different materials.

Although a method of forming the control electrode, first electrode,second electrode, gate electrode, and source/drain electrodes depends onthe materials thereof, examples of the method include the various typesof coating methods described above; a physical vapor deposition (PVD)method; pulsed laser deposition (PLD) method; arc discharge method;various types of chemical vapor deposition (CVD) methods including ametalorganic chemical vapor deposition (MOCVD) method; lift-offtechnique; shadow mask technique; and plating technique such aselectroplating, electroless plating, or combination thereof, and thesemay be used alone or in combination with a patterning method whereappropriate. Examples of the PVD method include (a) various types ofvapor deposition methods such as electron-beam heating, resistanceheating, flash deposition, and a technique in which a crucible isheated; (b) plasma deposition technique, (c) various types of sputteringsuch as diode sputtering, direct current (DC) sputtering, DC magnetronsputtering, radio frequency (RF) sputtering, magnetron sputtering, ionbeam sputtering, and bias sputtering; and (d) various types of ionplating such as a DC method, PF method, multi-cathode method, activatedreaction method, field evaporation method, high-frequency ion platingmethod, and reactive ion plating method. In the case of forming a resistpattern, for example, a resist film is formed as a result of applying aresist material, and the resist film is then patterned by aphotolithographic method, laser drawing method, electron beam drawingmethod, or X-ray drawing method. The resist pattern may be formed byusing a resist transfer method or the like. In the case of forming thecontrol electrode, first electrode, second electrode, gate electrode,and source/drain electrodes by an etching method, a dry etching methodor a wet etching method may be used. Examples of the dry etching methodinclude ion milling and reactive ion etching (RIE). Furthermore, thecontrol electrode, first electrode, second electrode, gate electrode,and source/drain electrodes may be formed by laser ablation, maskevaporation, laser transfer, or the like.

The insulating layer or gate insulting layer (hereinafter collectivelyreferred to as “gate insulating layer or the like”, where appropriate)may have a single layer structure or multilayer structure. Examples of amaterial used for the gate insulating layer or the like includeinorganic insulating materials traditionally used for a metallic oxidehigh-dielectric insulating film [such as a silicon oxide-based material,silicon nitride (SiN_(Y)), aluminum oxide (Al₂O₃), and hafnium oxide(HfO₂)] and also include organic insulating materials (organic polymer)such as linear hydrocarbons in which one end has a functional group thatcan be bonded to the control electrode and gate electrode [for instance,polymethylmethacrylate (PMMA); polyvinyl phenol (PVP); polyvinyl alcohol(PVA); polyimide; polycarbonate (PC); polyethylene terephthalate (PET);polystyrene; silanol derivatives (silane coupling agent) such asN-2(aminoethyl)-3-aminopropyltrimethoxysilane(AEAPTMS),3-mercaptopropyltrimethoxysilane (MPTMS), andoctadecyltrichlorosilane (OTS); octadecanethiol; and dodecylisocyanate], and these material may be used in combination. Examples ofthe silicon oxide-base material include silicon oxide (SiO_(x)), boronphosphorus silicate glass (BPSG), phosphorus silicate glass (PSG), boronsilicate glass (BSG), arsenic silicate glass (AsSG), lead silicate glass(PbSG), silicon oxynitride (SiON), spin on glass (SOG), and alow-permittivity SiO₂-base material (such as polyarylether,cycloperfluorocarbon polymer, benzocyclobutene, cyclic fluorine resin,polytetrafluoroethylene, arylether fluoride, polyimide fluoride,amorphous carbon, or organic SOG).

Examples of a method of forming the gate insulating layer or the likeinclude, in addition to the above coating method, a lift-off technique,sol-gel method, electrodeposition method, and shadow mask technique, andthese method may be used alone or in combination with a patterningtechnique.

Furthermore, the gate insulating layer can be formed as a result ofoxidizing or nitriding a surface of the control electrode or gateelectrode and can be formed as a result of forming an oxide film ornitride film on a surface of the control electrode or gate electrode. Amethod of oxidizing a surface of the control electrode or gate electrodedepends on the material used for the control electrode or gateelectrode, and examples of the method include an oxidation method usingO₂ plasma and anodic oxidation method. A method of nitriding a surfaceof the control electrode or gate electrode depends on the material usedfor the control electrode or gate electrode, and examples of the methodinclude a nitriding method using N₂ plasma. Moreover, in an Auelectrode, for example, a technique such as a dipping method can be usedto cover a surface of the control electrode or gate electrode in theself-organizing manner with the aid of insulating molecules having afunctional group which can chemically form a bond with the controlelectrode or gate electrode, such as linear hydrocarbons in which oneend is modified by a mercapto group, so that the insulating layer isformed on a surface of the control electrode or gate electrode.Moreover, a surface of the control electrode or gate electrode can bemodified by a silanol derivative (silane coupling agent), thereby beingable to form the insulating layer.

In the case where the thin-film device of an embodiment of the presentdisclosure is applied to or used for a display apparatus and varioustypes of electronic equipment, the thin-film device may be provided as amonolithic integrated circuit in which the second substrate isintegrated with a large number of thin-film devices (such as anelectronic device and semiconductor device). In addition, the individualthin-film devices may be cut to be individuated and may be provided asdiscrete parts. The thin-film device may be sealed by resin.

Example 1

The example 1 relates to the thin-film devices of the first to thirdembodiments of the present disclosure, the method of manufacturing thethin-film devices of the first to third embodiments, and the method ofmanufacturing the image display apparatus of the present disclosure.FIG. 1A is a partial cross-sectional view schematically illustrating athin-film device 10A of the example 1. FIG. 1B is a partialcross-sectional view schematically illustrating a supporting base andother portions and serves to illustrate a method of manufacturing thethin-film device of the example 1.

The thin-film device 10A of the example 1 includes a first substrate 21,a second substrate 22 formed on the first substrate 21, and an activeelement 30 formed on the second substrate 22.

In accordance with the first embodiment of the present disclosure, aresin material is used to form the first substrate 21 and has a glasstransition temperature T_(g) of 180° C. or higher, and the secondsubstrate 22 is formed by using a thermosetting resin or energyray-curable resin.

In accordance with the second embodiment of the present disclosure, theresin material used for the first substrate 21 has a glass transitiontemperature T_(g) higher than the maximum (150° C., in particular) of aprocessing temperature during the formation of the active element 30.The second substrate 22 is formed by using a thermosetting resin orenergy ray-curable resin. In this case, the resin material used for thefirst substrate 21 has a glass transition temperature T_(g) of 180° C.or higher.

In accordance with the third embodiment of the present disclosure, anamorphous thermoplastic resin is employed as the resin material used forthe first substrate 21, and a thermosetting resin or ultraviolet curableresin is employed as the resin used for the second substrate 22. In thiscase, a polysulfone-based resin is employed as the amorphousthermoplastic resin used for the first substrate 21.

In the thin-film device 10A of the example 1, a peel strength (inparticular, 90° peel strength) is exhibited to a supporting base 20 inthe range from 1.0 N/cm (0.1 kgf/cm) to 4.9 N/cm (0.5 kgf/cm). In thiscase, a polysulfone resin is employed as the amorphous thermoplasticresin used for the first substrate 21 as described above, and anepoxy-based resin is employed as the thermosetting resin used for thesecond substrate 22.

In the example 1, the active element 30 includes first and secondelectrodes, an active layer formed between the first and secondelectrodes, and a control electrode formed so as to face the activelayer through an insulating layer. The active layer 30 is specificallyformed as an FET and more specifically formed as a TFT. The first andsecond electrodes correspond to source/drain electrodes 33, the controlelectrode corresponds to a gate electrode 31, and the insulating layercorresponds to a gate insulating layer 32, and the active layercorresponds to a channel-forming region 34. A voltage is applied to thecontrol electrode with the result that a current flowing from the firstelectrode toward the second electrode through the active layer iscontrolled.

In this case, the active element 30 formed as the TFT is furtherspecifically formed so as to have a bottom gate and bottom contact-typeconfiguration. The active element 30 has (A) the gate electrode 31(corresponding to the control electrode) formed on the second substrate22; (B) the gate insulating layer 32 (corresponding to the insulatinglayer) formed on the gate electrode 31 and second substrate 22; (C) thesource/drain electrodes 33 (corresponding to the first and secondelectrodes) formed on the gate insulating layer 32; and (D) thechannel-forming region 34 (corresponding to the active layer) formedbetween the source/drain electrodes 33 so as to overlie the gateinsulating layer 32, the channel-forming region 34 being formed as alayer of an organic semiconductor material.

In the example 1, gold (Au) is used to form the control electrode (gateelectrode 31) and first and second electrodes (source/drain electrodes33), SiO₂ is used to form the insulating layer (gate insulating layer32), and triisopropylsilyl (TIPS)-pentacene is used to form the activelayer (channel-forming region 34).

A method of manufacturing a thin-film device and a method ofmanufacturing an image display apparatus according to the example 1 willbe hereinafter described. In the following description, the controlelectrode and gate electrode are collectively referred to as a gateelectrode, the first and second electrodes and source/drain electrodesare collectively referred to as source/drain electrodes, the insulatinglayer and gate insulating layer are collectively referred to as a gateinsulating layer, and the active layer and channel-forming region arecollectively referred to as a channel-forming region.

A solution of an organic semiconductor material is prepared in advance.In particular, TIPS-pentacene as the organic semiconductor material of 1gram was dissolved in 1,2,3,4-tetrahydronaphthalene as an organicsolvent of 100 gram. In addition, a first substrate-forming solution anda second substrate-forming solution are prepared, the firstsubstrate-forming solution being prepared as a result of dissolvingpolysulfone (glass transition temperature T_(g): 180° C.) inn-methylpyrrolidone, and the second substrate-forming solution beingprepared as a result of dissolving an epoxy-based resin (in particular,o-cresol novolac epoxy resin) in cyclopentanone.

Process-100

The first substrate 21 is first formed on the supporting base 20(supporting base) by a coating method using the resin material, and thesecond substrate 22 is then formed on the first substrate 21 by using athermosetting resin. Alternatively, the first substrate 21 is formed onthe supporting base 20 by a coating method using an amorphousthermoplastic resin, and the second substrate 22 is then formed on thefirst substrate 21 by using a thermosetting resin. In particular, thefirst substrate-forming solution is applied onto a glass substrateprovided as the supporting base 20 by using a bar coater and is thendried so as to have a thickness of 100 μm, thereby forming the firstsubstrate 21 on the supporting base 20. The second substrate-formingsolution is subsequently applied on the first substrate 21 and is thenthermally cured by drying so as to have a thickness of 10 μm, therebyforming the second substrate 22 on the first substrate 21.

The active section 30 is subsequently formed on the second substrate 22.

Process-110

In order to form the active section 30, the gate electrode 31 is formedon the second substrate 22. In particular, a resist layer (notillustrated), in which a portion in which the gate electrode 31 isformed has been removed, is formed by a lithographic technique. Atitanium (Ti) layer (not illustrated) as an adhesion layer and a gold(Au) layer as the gate electrode 31 are formed on the entire surface ofthe resultant product by a vapor deposition method in sequence, and theresist layer is then removed. The gate electrode 31 can be formed by aso-called lift-off technique in this manner.

Process-120

The gate insulating layer 32 is then formed on the entire surface of theresultant product, specifically on the gate electrode 31 and secondsubstrate 22. In more particular, the gate insulating layer 32 is formedusing SiO₂ on the gate electrode 31 and second substrate 22 by asputtering method. In the formation of the gate insulating layer 32, thegate electrode 31 is partially covered with a hard mask, thereby beingable to form the connection portion (not illustrated) of the gateelectrode 31 without a photolithography process.

Process-130

The source/drain electrodes 33 are then formed on the gate insulatinglayer 32 in the form of gold (Au) layers. In particular, a titanium (Ti)layer (not illustrated) as an adhesion layer having a thickness ofapproximately 0.5 nm and gold (Au) layers as the source/drain electrodes33 having a thickness of 25 nm are formed by a vapor deposition methodin sequence. In the formation of these layers, the gate insulating layer32 is partially covered with a hard mask, thereby being able to form thesource/drain electrodes 33 (not illustrated) without a photolithographyprocess.

Process-140

Then, the solution of the organic semiconductor material is applied onthe gate insulating layer 32 at a position at least between thesource/drain electrodes 33 and is subsequently dried, thereby formingthe channel-forming region 34 in the form of a layer of the organicsemiconductor material. In particular, the layer of the organicsemiconductor material is formed by a spin coat method using thesolution of the organic semiconductor material described above. Theresultant layer of the organic semiconductor material is subsequentlydried at a temperature of 90° C. for an hour. The channel-forming region34 (active layer) can be formed in this manner (see FIG. 1B).

Alternately, the layer of the organic semiconductor material is formedby an ink-jet printing technique using the solution of the organicsemiconductor material described above. The resultant layer of theorganic semiconductor material is subsequently dried at a temperature of90° C. for an hour, thereby also being able to form the channel-formingregion 34 (active layer).

Process-150

Then, a passivation layer (not illustrated) is formed on the entiresurface of the resultant product, and wiring (not illustrated) connectedto the gate electrode 31 and source/drain electrodes 33 is formed as aresult of printing and subsequent calcining of silver paste. In thiscase, a temperature at which the silver paste is calcined is the maximum(150° C., in particular) of a processing temperature in a set of theprocesses of manufacturing the thin-film device and image displayapparatus. In this manner, a bottom gate and bottom contact-type FET(TFT, in particular) can be produced.

Process-160

Then, the supporting base 20 is removed from the first substrate 21. Inparticular, cut lines are formed in the second substrate 22 and firstsubstrate 21 formed so as to overlie the supporting base 20, and wateris made to intrude from the cut lines, thereby removing the supportingbase 20 from the first substrate 21. In this manner, the thin-filmdevice (TFT) 10A of the example 1 can be produced. Furthermore, an imagedisplay apparatus including the thin-film device 10A of the example 1can be produced. In order to manufacture the image display apparatus, animage display (in particular, an image display including an organicelectroluminescence device, microcapsule-type electrophoretic displaydevice, or semiconductor light-emitting device) may be formed on orabove the thin-film device 10A by a traditional method after thisprocess.

In the method of manufacturing a thin-film device and the method ofmanufacturing an image display apparatus according to the example 1, theactive element 30 is formed so as to overlie the two-layered structureincluding the first substrate 21 and second substrate 22, and thesupporting base 20 is then removed from the first substrate 21. Thethin-film device 10A can be therefore manufactured through a simple andeasy process without large-scale manufacturing equipment.

In addition, since the active element 30 is formed on the secondsubstrate 22 in a state in which the first substrate 21 is covered withthe second substrate 22, the first substrate 21 can be prevented fromthe occurrence of cracks, for instance, resulting from the contact ofthe first substrate 21 with a ketone-based solvent such as acetoneduring the formation of the active element 30. For example, in atraditional technique of manufacturing an organic transistor, a plasticfilm is attached to a supporting base by using an adhesive material orthe like, the organic transistor is formed on the plastic film, and theplastic film on which the organic transistor has been formed is thenremoved from the supporting base. As compared with such a technique, anadhesive material is not used in an embodiment of the presentdisclosure, a typical problem can be therefore overcome, in which theadhesive material partially remains on the plastic film in the removalof the plastic film from the supporting base and is then removed in anadditional process.

The occurrence of damage in the first substrate 21 can be evaluated, forexample, in the following manner: the first substrate 21 is immersedinto acetone and is allowed to stand at a temperature of 60° C. for 30minutes; and the first substrate 21 is subsequently retrieved from thesolvent, and the surface of the first substrate 21 is then visuallyobserved. In order to evaluate the 90° peel strength of the firstsubstrate 21 to the supporting base 20, TENSILON (commercially availablefrom A&D Company, Limited) is used. A surface of the glass substrate iswashed to be cleaned, and the first substrate-forming solution isapplied onto the glass substrate with a bar coater and is then dried soas to have a thickness of 100 μm, thereby forming the fist substrate 21on the glass substrate. Then, the 90° peel strength may be measured inaccordance with JIS K 6854-1:1999.

Since the first substrate 21 is formed on the supporting base 20 by acoating method, the first substrate 21 can be easily formed, and bubblesare less likely to be caused between the supporting base 20 and thefirst substrate 21. In the thin-film device 10A of the example 1, thematerials used for the first substrate 21 and second substrates 22 andthe properties, details, and particulars of the materials are defined.The thin-film device 10A can be therefore manufactured through a simpleand easy process without large-scale manufacturing equipment.

In place of the epoxy-based resin, a diallyl phthalate resin is appliedonto the first substrate 21 to form the second substrate 22, andultraviolet is radiated to cure the second substrate 22, therebyproducing a two-layered structure of the substrates. Also in this case,the first substrate 21 can be prevented from the occurrence of cracks,for instance, resulting from the contact of the first substrate 21 witha ketone-based solvent such as acetone during the formation of theactive element 30.

Except that the second substrate 22 was not formed, the same processesas employed in the example 1 were similarly used, thereby manufacturinga thin-film device of a comparison example 1A. As a result, in the casewhere the first substrate 21 contacted with a ketone-based solvent suchas acetone during the formation of the active element 30, for example,the first substrate 21 was not dissolved but suffered from damage suchas the occurrence of cracks. It is believed that such cracks result fromstress caused inside the first substrate 21.

In a comparison example 1B, the first substrate 21 was formed as a layerof a polyimide resin (thickness after drying: 100 μm) on the supportingbase 20. In addition, the second substrate 22 was not formed, and thesame processes as employed in the example 1 were similarly used exceptthese changes, thereby manufacturing a thin-film device. As a result, inthe process the same as the process-160 of the example 1, the supportingbase 20 had difficulty to be removed from the layer of the polyimideresin.

In a comparison example 1C, except that polyacrylate having a glasstransition temperature T_(g) of 110° C. was used to form the firstsubstrate 21 on the supporting base 20, the same processes as employedin the example 1 were similarly used, thereby manufacturing a thin-filmdevice. In particular, as in the case of the example 1, o-cresol novolacepoxy resin was used to form the second substrate 22 on the firstsubstrate 21. As a result, the first substrate 21 peeled from thesupporting base 20 during the formation of the active element 30 withthe result that the manufacturing of a thin-film device failed.

Example 2

The example 2 is a modification of the example 1. In the example 2, athin-film device 10B is formed as a bottom gate and top contact-type FET(in particular, TFT). With reference to FIG. 2A which is a partialcross-sectional view schematically illustrating the FET of the example2, the FET includes (A) a gate electrode 31 (corresponding to the gateelectrode) formed on the second substrate 22; (B) a gate insulatinglayer 32 (corresponding to the insulating layer) formed on the gateelectrode 31 and second substrate 22; (C) a channel-forming region 34(corresponding to the active layer) and channel-forming region extension35 formed on the gate insulating layer 32, the channel-forming region 34and channel-forming region extension 35 being used as layers of anorganic semiconductor material; and (D) source/drain electrodes 33(corresponding to the first and second electrodes) formed on thechannel-forming region extension 35.

A method of manufacturing a thin-film device 10B of the example 2 willbe hereinafter described.

Process-200

The first substrate 21 and the second substrate 22 are first formed onthe supporting base 20 in sequence as in the case of the process-100 ofthe example 1. The gate electrode 31 is formed on the second substrate22 as in the case of the process-110 of the example 1, and the gateinsulating layer 32 is then formed on the entire surface of theresultant product, specifically on the gate electrode 31 and secondsubstrate 22, as in the case of the process-120 of the example 1.

Process-210

As in the case of the process-140 of the example 1, the solution of theorganic semiconductor material is then applied onto the gate insulatinglayer 32 and is subsequently dried, thereby forming the channel-formingregion 34 and channel-forming region extension 35 as the layers of theorganic semiconductor material.

Process-220

The source/drain electrodes 33 are formed on the channel-forming regionextension 35 such that the channel-forming region 34 is positionedbetween the source/drain electrodes 33. In particular, as in the case ofthe process-130 of the example 1, a titanium (Ti) layer (notillustrated) as an adhesion layer and gold (Au) layers as thesource/drain electrodes 33 are formed in sequence by a vapor depositionmethod. In the formation of these layers, the channel-forming regionextension 35 is partially covered with a hard mask, thereby being ableto form the source/drain electrodes 33 (not illustrated) without aphotolithography process.

Process-230

Then, a passivation layer (not illustrated) and wiring (not illustrated)are formed as in the case of the example 1, and the supporting base 20is subsequently removed from the first substrate 21, thereby being ableto complete the thin-film device 10B of the example 2.

Example 3

The example 3 is also a modification of the example 1. In the example 3,a thin-film device 10C is formed as a top gate and bottom contact-typeFET (in particular, TFT). With reference to FIG. 2B which is a partialcross-sectional view schematically illustrating the FET of the example3, the FET includes (A) the source/drain electrodes 33 (corresponding tofirst and second electrodes) formed on the second substrate 22; (B) thechannel-forming region 34 (corresponding to the active layer) formed onthe second substrate 22 so as to be positioned between the source/drainelectrodes 33, the channel-forming region 34 being formed as a layer ofan organic conductor material; (C) the gate insulating layer 32(corresponding to the insulating layer) formed on the channel-formingregion 34; and (D) the gate electrode 31 (corresponding to the controlelectrode) formed on the gate insulating layer 32.

A method of manufacturing a thin-film device of the example 3 will behereinafter described.

Process-300

As in the case of the process-100 of the example 1, the first substrate21 and second substrate 22 are first formed on the supporting base 20 insequence. Then, as in the case of the process-130 of the example 1, thesource/drain electrodes 33 are formed on the second substrate 22. Thesolution of the organic semiconductor material is applied onto theentire surface of the resultant product, specifically on thesource/drain electrodes 33 and second substrate 22, and is subsequentlydried as in the case of the process-140 of the example 1, therebyforming the channel-forming region 34 (active layer) as a layer of theorganic conductor material.

Process-310

The gate insulating layer 32 is then formed on the entire surface of theresultant product in the same manner as the process-120 of theexample 1. The gate electrode 31 is subsequently formed on the gateinsulating layer 32 in the same manner as the process-110 of the example1 so as to overlie the channel-forming region 34.

Process-320

Then, a passivation layer (not illustrated) and wiring (not illustrated)are formed as in the case of the example 1, and the supporting base 20is subsequently removed from the first substrate 21, thereby being ableto complete the thin-film device 10C of the example 3.

Example 4

The example 4 is also a modification of the example 1. In the example 4,a thin-film device 10D is formed as a top gate and top contact-type FET(in particular, TFT). With reference to FIG. 3A which is a partialcross-sectional view schematically illustrating the FET of the example4, the FET includes (A) the channel-forming region 34 (corresponding tothe active layer) and channel-forming region extension 35 formed on thesecond substrate 22, the channel-forming region 34 and channel-formingregion extension 35 being formed as layers of an organic conductormaterial; (B) the source/drain electrodes 33 (corresponding to the firstand second electrodes) formed on the channel-forming region extension35; (C) the gate insulating layer 32 (corresponding to the insulatinglayer) formed on the source/drain electrodes 33 and channel-formingregion 34; and (D) the gate electrode 31 (corresponding to the controlelectrode) formed on the gate insulating layer 32.

A method of manufacturing a thin-film device of the example 4 will behereinafter described.

Process-400

As in the case of the process-100 of the example 1, the first substrate21 and second substrate 22 are first formed on the supporting base 20 insequence. Then, as in the case of the process-140 of the example 1, thesolution of the organic semiconductor material is applied onto thesecond substrate 22 and is subsequently dried, thereby forming thechannel-forming region 34 and channel-forming region extension 35 aslayers of the organic semiconductor material.

Process-410

The source/drain electrodes 33 are then formed on the channel-formingregion extension 35 in the same manner as the process-130 of the example1.

Process-420

The gate insulating layer 32 is subsequently formed on the entiresurface of the resultant product in the same manner as the process-120of the example 1. The gate electrode 31 is then formed on the gateinsulating layer 32 in the same manner as the process-110 of the example1 so as to overlie the channel-forming region 34.

Process-430

Then, a passivation layer (not illustrated) and wiring (not illustrated)are formed as in the case of the example 1, and the supporting base 20is subsequently removed from the first substrate 21, thereby being ableto complete the thin-film device 10D of the example 4.

Example 5

The example 5 is a modification of the examples 1 to 4. In the example5, a resin material which is not cured or cross-linked, specificallypolysulfone, is employed as the resin material used for the firstsubstrate 21. The material used for the second substrate 22 contains thematerial used for the first substrate 21. Except these points, athin-film device 10D of the example 5 can be manufactured so as to haveformation and structure the same as those of the thin-film devices ofthe examples 1 to 4 and can be manufactured by the same methods asemployed in the examples 1 to 4. The detailed description of the methodof manufacturing a thin-film device according to the example 5 istherefore omitted.

Example 6

The example 6 is also a modification of the example 1. In the example 6,the active element of the example 6 is specifically formed as atwo-terminal device. In more particular, with reference to FIG. 3B whichis a partial cross-sectional view schematically illustrating a thin-filmdevice 10E, the thin-film device 10E includes a first electrode 41, asecond electrode 42, and an active layer 43 disposed between the firstelectrode 41 and second electrode 42. In this case, the active layer 43is formed as a layer of an organic semiconductor material. Lightemission to the active layer 43 causes electric power to be generated.In other words, the thin-film device 10E of the example 6 functions as aphotoelectric transducer or solar battery. Furthermore, the thin-filmdevice 10E serves as a light-emitting device in which the active layer43 emits light as a result of application of a voltage between the firstelectrode 41 and second electrode 42.

Except these points, the thin-film device 10E of the example 6 can bemanufactured so as to basically have formation and structure the same asthose of the thin-film device 10A of the example 1, and the detaileddescription of the method of manufacturing a thin-film device accordingto the example 6 is therefore omitted. The same process as theprocess-100 of the example 1 is conducted, and the first electrode 41,active layer 43, and second electrode 42 are then formed in sequence inthe substantially same manners as the processes-130, 140, 130 of theexample 1, respectively. Wiring is subsequently formed in the samemanner as the process-150 of the example 1, and the supporting base 20is then removed from the first substrate 21 in the same manner as theprocess-160 of the example 1, thereby being able to produce thethin-film device 10E of the example 6.

Although embodiments of the present disclosure have been described withreference to the preferable examples, embodiments of the presentdisclosure are not limited to the above examples. The structure,formation, forming conditions, and manufacturing conditions of each ofthe thin-film devices are provided just as examples and can beappropriately changed. In the case where the thin-film devices producedin embodiments of the present disclosure are applied to or used for adisplay apparatus and various types of electronic equipment, forexample, the thin-film devices may be provided as a monolithicintegrated circuit in which a substrate is integrated with a largenumber of the thin-film devices or may be provided as discrete partswhich are produced as a result of cutting and then individuating theindividual thin-film devices. Although the thin-film devices are mainlyformed as a three-terminal or two-terminal device in the examples, thethin-film devices may be provided as an organic electroluminescencedevice, microcapsule-type electrophoretic display device, orsemiconductor light-emitting device each having typical formation andstructure. In this case, a traditional method may be employed tomanufacture such an organic electroluminescence device,microcapsule-type electrophoretic display device, or semiconductorlight-emitting device.

The present disclosure contains subject matter related to that disclosedin Japanese Priority Patent Application JP 2011-081404 filed in theJapan Patent Office on Apr. 1, 2011, the entire contents of which arehereby incorporated by reference.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

What is claimed is:
 1. A method of manufacturing a thin-film device, themethod comprising: forming a first substrate on a supporting base by acoating method, the first substrate being formed by using a resinmaterial; forming a second substrate on the first substrate by using anyone of a thermosetting resin and energy ray-curable resin; forming anactive element on the second substrate; and removing the supporting basefrom the first substrate, wherein the resin material used to form thefirst substrate has a glass transition temperature of at least 180° C.2. The method of manufacturing a thin-film device according to claim 1,wherein: any one of a non-curable resin material and non-cross-linkedresin material is used to form the first substrate, and the materialused for the second substrate contains a component of the resin materialused for the first substrate.
 3. The method of manufacturing a thin-filmdevice according to claim 1, wherein a peel strength with respect to thesupporting base is in the range from 1.0 N/cm to 4.9 N/cm.
 4. The methodof manufacturing a thin-film device according to claim 1, wherein theactive element includes: first and second electrodes; an active layerformed between the first and second electrodes; and a control electrodewhich faces the active layer through an insulating layer.
 5. The methodof manufacturing a thin-film device according to claim 4, wherein theactive element is formed as a thin-film transistor, the first and secondelectrodes function as source/drain electrodes, the control electrodefunctions as a gate electrode, the insulating layer functions as a gateinsulating layer, and the active layer functions as a channel-formingregion.
 6. The method of manufacturing a thin-film device according toclaim 4, wherein an organic semiconductor material is used to form theactive layer.
 7. The method of manufacturing a thin-film deviceaccording to claim 1, wherein the active element includes: first andsecond electrodes; and an active layer formed between the first andsecond electrodes.
 8. The method of manufacturing a thin-film deviceaccording to claim 1, wherein the active element is formed as an organicelectroluminescence device.
 9. The method of manufacturing a thin-filmdevice according to claim 1, wherein the active element is formed as amicrocapsule-type electrophoretic display device.
 10. A method ofmanufacturing an image display apparatus, the method comprising themethod of manufacturing a thin-film device according to claim 1, whereinthe thin-film device is included in the image display apparatus as adisplay portion of the image display apparatus.
 11. A method ofmanufacturing a thin-film device, the method comprising: forming a firstsubstrate on a supporting base by a coating method, the first substratebeing formed by using a resin material; forming a second substrate onthe first substrate by using any one of a thermosetting resin and energyray-curable resin; forming an active element on the second substrate;and removing the supporting base from the first substrate, wherein, theresin material used for the first substrate has a glass transitiontemperature higher than the maximum of a processing temperature duringthe formation of the active element.
 12. The method of manufacturing athin-film device according to claim 11, wherein the resin material usedto form the first substrate has a glass transition temperature of atleast 180° C.
 13. The method of manufacturing a thin-film deviceaccording to claim 11, wherein a peel strength with respect to thesupporting base is in the range from 1.0 N/cm to 4.9 N/cm.
 14. A methodof manufacturing a thin-film device, the method comprising: forming afirst substrate on a supporting base by a coating method, the firstsubstrate being formed by using an amorphous thermoplastic resin;forming a second substrate on the first substrate by using any one of athermosetting resin and ultraviolet curable resin; forming an activeelement on the second substrate; and removing the supporting base fromthe first substrate.
 15. The method of manufacturing a thin-film deviceaccording to claim 14, wherein a polysulfone-based resin is employed asthe amorphous thermoplastic resin used for the first substrate.
 16. Themethod of manufacturing a thin-film device according to claim 15,wherein any one of a polysulfone resin, polyether sulfone resin, andpolyetherimide resin is employed as the amorphous thermoplastic resinused for the first substrate.
 17. The method of manufacturing athin-film device according to claim 14, wherein epoxy-based resin isemployed as the thermosetting resin used for the second substrate.